Implementing a shared-care approach to improve the management of patients with pulmonary arterial hypertension

Patients with pulmonary arterial hypertension (PAH) may present to internists, rheumatologists, cardiologists, or pulmonologists. This breadth of clinicians who encounter PAH patients, together with the complicated nature of PAH as a disease entity, argues for a shared-care approach to the management of these patients. This review describes the contributions of several key specialties to PAH management and outlines the collaborative PAH management model in place at our institution.     

vWF/ADAMTS13 is associated with on-aspirin residual platelet reactivity and clinical outcome in patients with stable coronary artery disease

Background

The mechanisms behind residual platelet reactivity (RPR) despite aspirin treatment are not established. It has been shown that coronary artery disease (CAD) patients with high on-aspirin RPR have elevated levels of von Willebrand factor (vWF). ADAMTS13 is a metalloprotease cleaving ultra large vWF multimers into less active fragments.Our aim was to investigate whether ADAMTS13 and vWF/ADAMTS13 ratio were associated with high RPR, and further with clinical endpoints after 2 years.

Methods

Stable aspirin-treated CAD patients (n?=?999) from the ASCET trial. RPR was assessed by PFA-100. ADAMTS13 antigen and activity were analysed using chromogenic assays. Endpoints were a composite of acute myocardial infarction, stroke and death.

Results

The number of patients with high RPR was 258 (25.8%). Their serum thromboxane B₂ (TxB₂) levels were low, indicating inhibition of COX-1. They had significantly lower levels of ADAMTS13 antigen compared to patients with low RPR (517 vs 544 ng/mL, p?=?0.001) and significantly lower ADAMTS13 activity (0.99 vs 1.04 IU/mL, p?=?0.020). The differences were more pronounced when relating RPR to ratios of vWF/ADAMTS13 antigen and vWF/ADAMTS13 activity (p?<?0.001, both). We found an inverse correlation between vWF and ADAMTS13 antigen (r?=??0.14, p?<?0.001) and ADAMTS13 activity (r?=??0.11, p?<?0.001). No correlations between TxB₂ and ADAMTS13 antigen or activity, were observed, implying that ADAMTS13 is not involved in TxB2 production. Patients who experienced endpoints (n?=?73) had higher vWF level (113 vs 105%, p?=?0.032) and vWF/ADAMTS13 antigen ratio (0.23 vs 0.20, p?=?0.012) compared to patients without. When dichotomizing vWF/ADAMTS13 antigen at median level we observed that patients above median had higher risk for suffering endpoints, with an adjusted OR of 1.86 (95% CI 1.45, 2.82).

Conclusion

These results indicate that ADAMTS13 is of importance for RPR, and that it in combination with vWF also is associated with clinical endpoints in stable CAD patients on aspirin.

Trial registration

Clinicaltrials.gov NCT00222261. Registered 13.09.2005. Retrospectively registered.