Accuracy of echocardiographic assessment of pulmonary hypertension severity and right ventricular dysfunction in patients with chronic thromboembolic pulmonary hypertension.

AIM: Chronic thromboembolic pulmonary hypertension (CTEPH) results from chronic thrombotic occlusion of the pulmonary arterial circulation and may be potentially cured by pulmonary thromboendarterectomy. Echocardiography is the most practical modality for the assessment of right ventricular function and right heart pressures before and after surgery. However, there is scant data on how these estimates compare with the "gold standards" of invasive right heart catheterization and CT and MR scanning. METHODS: The records of 100 consecutive patients with CTEPH who subsequently underwent pulmonary thromboendarterectomy at our institution were studied. Right atrial (RA) and right ventricular (RV) systolic pressure estimated at preoperative echocardiography were compared with measurements at preoperative cardiac catheterization. In addition, preoperative echocardiographic estimates of RV systolic function by visual assessment and by calculation of RV index of myocardial performance were compared with preoperative measurements of RV ejection fraction (EF) by computed tomography (CT) or magnetic resonance (MR) scanning. RESULTS: Although estimates of RA and PA systolic pressures by echocardiography correlated significantly with those at cardiac catheterization (p<0.0001) in patients with CTEPH, Bland-Altman analysis demonstrated significant variation in these measurements compared with cardiac catheterization. Cohen's Kappa analysis demonstrated that agreement between echo and cath derived values was slight (κ=0.1). RVEF assessed by CT or MR scanning correlated with echocardiographic visual assessment of RV systolic function (P<0.0001), and with RIMP (P=0.001), but actual measurements of right ventricular ejection fraction at a given assessment of right ventricular function by RIMP or visual assessment varied widely CONCLUSION: Caution is warranted in over-reliance on echo derived measurements of right heart hemodynamics and function in the setting of pulmonary hypertension, and where the clinical scenario calls the data into question, a low threshold should be maintained for proceeding to more advanced and invasive modalities of evaluation.

Effect of enhanced external counterpulsation on circulating CD34+ progenitor cell subsets.

BACKGROUND: Enhanced external counterpulsation (EECP) is associated with improvement in endothelial function, angina and quality of life in patients with symptomatic coronary artery disease, although the mechanisms underlying the observed clinical benefits are not completely clear. The purpose of this study was to examine the effects of EECP on circulating haematopoietic progenitor cells (HPCs) and endothelial progenitor cells (EPCs) in patients with refractory angina. We compared HPC and EPC counts between patients scheduled for EECP and patients with normal angiographic coronary arteries, with and without coronary endothelial dysfunction. We hypothesized that an increase in circulating bone marrow derived progenitor cells in response to EECP may be part of the mechanism of action of EECP. METHODS: Thirteen consecutive patients scheduled to receive EECP treatment were prospectively enrolled. Clinical characteristics were recorded and venous blood (5 ml) was drawn on day 1, day 17, day 35 (final session) and one month post completion of EECP therapy. Buffy coat was extracted and HPCs and EPCs were counted by flow cytometry. RESULTS: Median Canadian Cardiovascular Society (CCS) angina class decreased and Duke Activity Status Index (DASI) functional score increased significantly (both, p < 0.05) in response to EECP, an effect that was maintained at one month after termination of treatment. Flow cytometric analysis revealed an accompanying significant increase in CD34+, CD133+ and CD34+, CD133+ CPC counts over the course of treatment (p < 0.05). DASI scores correlated significantly with CD34+ (R = 0.38 p = 0.02), CD133+ (R = 0.5, p = 0.006) and CD34+, CD133+ (R = 0.47, p = 0.01) CPC counts. CONCLUSION: This study shows that HPCs, but not EPCs are significantly increased in response to EECP treatment and correlate with reproducible measures of clinical improvement. These findings are the first to link the functional improvement observed with EECP treatment with increased circulating progenitor cells.

Stem cells and transplant vasculopathy.

Transplant vasculopathy (TV) remains the most common cause of long-term mortality in cardiac transplant recipients. Treatment options are limited, and traditionally, the only definitive treatment was retransplantation. An increasing understanding of the pathophysiology of TV in recent years, in particular as an immune phenomenon, has stimulated important research into new strategies for the prevention of the progression of this condition. Coupled with this, the emerging evidence in recent years of the role of resident and circulating progenitor cells in the pathogenesis of vascular disease has opened new horizons in the understanding of the pathogenesis of TV and, in addition, of the potential mechanisms underlying the beneficial effects of new and exciting therapeutic strategies. In this paper, the current understanding of the pathogenesis of TV and the possible role of stem and progenitor cells in this regard will be described. Recent data on new pharmacotherapeutic options for the prevention and treatment of TV will be examined, and the possible mechanistic contribution of circulating and resident stem and progenitor cells will be discussed. Finally, the implications of the current status of our understanding for the development of new innovative therapeutic options for TV will be explored.