External validation of established risk adjustment models for procedural complications after percutaneous coronary intervention

BACKGROUND

Workable risk models for patients undergoing percutaneous coronary intervention (PCI) are needed urgently.

OBJECTIVE

To validate two proposed risk adjustment models (Mayo Clinic Risk Score (MC), USA and North West Quality Improvement Programme (NWQIP), UK models) for in-hospital PCI complications on an independent dataset of relatively high risk patients undergoing PCI.

SETTING

Tertiary centre in northern England.

METHODS

Between September 2002 and August 2006, 5034 consecutive PCI procedures (validation set) were performed on a patient group characterised by a high incidence of acute myocardial infarction (MI; 16.1%) and cardiogenic shock (1.7%). Two external models-the NWQIP model and the MC model-were externally validated.

MAIN OUTCOME MEASURE

Major adverse cardiovascular and cerebrovascular events: in-hospital mortality, Q-wave MI, emergency coronary artery bypass grafting and cerebrovascular accidents.

RESULTS

An overall in-hospital complication rate of 2% was observed. Multivariate regression analysis identified risk factors for in-hospital complications that were similar to the risk factors identified by the two external models. When fitted to the dataset, both external models had an area under the receiver operating characteristic curve >or=0.85 (c index (95% CI), NWQIP 0.86 (0.82 to 0.9); MC 0.87(0.84 to 0.9)), indicating overall excellent model discrimination and calibration (Hosmer-Lemeshow test, p>0.05). The NWQIP model was accurate in predicting in-hospital complications in different patient subgroups.

CONCLUSIONS

Both models were externally validated. Both predictive models yield comparable results that provide excellent model discrimination and calibration when applied to patient groups in a different geographic population other than that in which the original model was developed.

Tuberculosis antigen-specific immune responses can be detected using enzyme-linked immunospot technology in human immunodeficiency virus (HIV)-1 patients with advanced disease

There are limited data on the efficacy of T cell-based assays to detect tuberculosis (TB) antigen-specific responses in immune-deficient human immunodeficiency virus (HIV) patients. The aim of this study is to determine whether TB antigen-specific immune responses can be detected in patients with HIV-1 infection, especially in those with advanced disease (CD4 T cell count < 300 cells/microl). An enzyme-linked immunospot (ELISPOT) assay, which detects interferon (IFN)-gamma secreted by T cells exposed to TB antigens, was used to assess specific immune responses in a prospective study of 201 HIV-1-infected patients with risk factors for TB infection, attending a single HIV unit. The performance of the ELISPOT assay to detect TB antigen-specific immune responses is independent of CD4 T cell counts in HIV-1 patients. The sensitivity and specificity of this assay for the diagnosis of active tuberculosis does not differ significantly from values obtained in immunocompetent subjects. The negative predictive value of the TB ELISPOT test is 98.2%. A positive predictive value of 86% for the diagnosis of active tuberculosis was found when the combined number of early secretory antigen target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) IFN-gamma spots to CD4 T cell count ratio was > 1.5. TB antigen-specific immune responses can be detected in HIV patients with low CD4 T cell counts using ELISPOT technology in a routine diagnostic laboratory and is a useful test to exclude TB infection in immune-deficient HIV-1 patients. A combination of TB antigen-specific IFN-gamma responses and CD4 T cell counts has the potential to distinguish active tuberculosis from latent infection.

Resolution of Severe Ischemia–Reperfusion Injury Post–Lung Transplantation After Administration of Endobronchial Surfactant

BACKGROUND

Ischemia-reperfusion injury (IRI) is a prominent cause of primary graft failure after lung transplantation and is associated with an altered surfactant profile. Experimental animal studies have found that replacement with exogenous surfactant administered via fiber-optic bronchoscopy (FOB) enhanced recovery from IRI with improved pulmonary compliance and gas exchange after lung transplantation. We report our clinical experience with FOB instillation of surfactant in severe IRI after human lung transplantation.

METHODS

This study is a retrospective review of 106 consecutive lung or heart-lung transplants performed at a single institution. Severe IRI was defined as diffuse roentgenographic alveolar infiltrates, worsening hypoxemia and decreased lung compliance within 72 hours of lung transplantation. One vial of surfactant (20 mg/ml phospholipid) was instilled into each segmental bronchus upon diagnosis of IRI.

RESULTS

Six patients (5 bilateral sequential and 1 re-do heart-lung transplant), mean age 46 years, were diagnosed with IRI and surfactant was administered at a mean of 37 hours (range 2.3 to 98) post-transplant. Mean graft ischemia time was 376 minutes (range 187 to 625) and cardiopulmonary bypass time 174 minutes (range 0 to 210). Mean Pao(2) [mm Hg]/Fio(2) ratio before and 48 hours after surfactant instillation was 70 and 223, respectively. Significant resolution of radiologic infiltrates was evident in all cases within 24 hours. Successful extubation occurred at a mean of 13.5 days and survival is presently 100% at 19 months (range 3 to 54).

CONCLUSIONS

Bronchoscopic instillation of surfactant improves oxygenation and prognosis after severe IRI in lung transplant recipients. It represents a cost-effective, relatively non-invasive therapeutic alternative to extracorporeal membrane oxygenation.

Stentless vs. stented aortic valve bioprostheses: a prospective randomized controlled trial

AIMS

We sought to assess the haemodynamic profile of the Freedom stentless aortic valve compared with a stented bioprosthesis in a randomized controlled trial using echocardiography.

METHODS AND RESULTS

Sixty patients (mean age 73 years) undergoing bioprosthetic aortic valve replacement (AVR) were randomized to either Sorin Freedom stentless (n=31) or Sorin More stented (n=29) valves. The primary endpoints were left ventricular mass index (LVMI) reduction at 6 and 12-months. We also assessed post-operative effective orifice area index (EOAI), aortic gradient and operative time. There were no significant differences in baseline characteristics. The stentless valve was associated with a lower post-operative gradient [PG 17 (12) vs. 31 (13) mmHg, P<0.0001] and greater EOAI [1.1 (0.3) vs. 0.8 (0.2) cm2/m2, P<0.0001]. A highly significant reduction in LVMI occurred by 6 months in both groups, but LVMI was significantly lower in the stentless group [LVMI 119 (39) vs. 135 (30) g/m2, P=0.05]. However, there was continued regression of left ventricular hypertrophy (LVH) in the stented but not in the stentless group, resulting in no significant difference in LVMI at 12 months [119 (36) vs. 126 (31) g/m2, P=0.42].

CONCLUSION

The use of the Sorin Freedom stentless bioprosthesis for AVR results in lower PG and greater EOA when compared with a Sorin More stented valve. This is associated with earlier regression of LVH.