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.

State-of-the-art implantable cardiac assist device therapy for heart failure: bridge to transplant and destination therapy.

Congestive heart failure is associated with poor quality of life (QoL) and low survival rates. The development of state-of-the-art cardiac devices holds promise for improved therapy in patients with heart failure. The field of implantable cardiac assist devices is changing rapidly with the emergence of continuous-flow pumps (CFPs). The important developments in this field, including pertinent clinical trials, registry reports, innovative research, and potential future directions are discussed in this paper.

Prolonged cardiac allograft survival using iodine 131 after human sodium iodide symporter gene transfer in a rat model.

BACKGROUND: Radioiodine is efficiently concentrated by tissues expressing the human sodium iodide symporter (hNIS). OBJECTIVE: To analyze the effects of iodine 131 on acute cardiac allograft rejection after ex vivo hNIS gene transfer in a rat model of cardiac allotransplantation. MATERIALS AND METHODS: Hearts from Brown Norway rats were perfused ex vivo either with UW (University of Wisconsin) solution (n = 9) or UW solution containing 1 x 10(9) pfu/mL of adenovirus 5 plus NIS (Ad-NIS) (n = 18). Donor hearts were transplanted heterotopically into the abdomen of Lewis rats, and recipients were treated on postoperative day 3 with either 15,000 microCi of (131)I or saline solution. The hearts were explanted when no longer beating, and were evaluated histologically for evidence of rejection and other changes. RESULTS: Grafts perfused with the Ad-NIS vector survived significantly longer in recipients injected with (131)I (mean [SD], 11.3 [1.9] days) compared with control animals not treated with (131)I (5.7 [0.65] days) (P < .001). Treatment with (131)I did not prolong graft survival in recipients of hearts that were not perfused with Ad-NIS (5.5 [1.0] vs 5.3 [0.8] days). In Ad-NIS (131)I-treated transplants, the level of myocardial damage on day 6 after surgery, when control hearts were rejected, was significantly lower (60.8 [28.0] vs 99.7 [0.8]; P < .05). CONCLUSION: Our findings indicate that (131)I, after NIS gene transfer, can effectively prolong cardiac allograft survival. To our knowledge, this is the first report of the use of NIS-targeted (131)I therapy in cardiac transplantation. Further studies are required to determine the mechanism of this effect and its potential for clinical application.

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.

Differences in activities of the enzymes of nucleotide metabolism and its implications for cardiac xenotransplantation.

Xenotransplantation is one be possible solution for a severe shortage of human organs available for transplantation. However, only a few studies addressed metabolic compatibility of transplanted animal organs. Our aim was to compare activities of adenosine metabolizing enzymes in the heart of different species that are relevant to clinical or experimental xenotransplantation. We noted fundamental differences: ecto-5' nucleotidease (E5' N) activity was 4-fold lower in pig and baboon hearts compared to the human hearts while mouse activity was compatible with human and rat activity was three times higher than human. There also were significant differences in AMP-deaminase (AMPD), adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities. We conclude that differences in nucleotide metabolism may contribute to organ dysfunction after xenotransplantation.

Is early anticoagulation with warfarin necessary after bioprosthetic aortic valve replacement?

OBJECTIVES: Freedom from anticoagulation is the principal advantage of bioprosthesis; however, the American Heart Association/American College of Cardiology and the American College of Chest Physicians guidelines recommend early anticoagulation with heparin, followed by warfarin for 3 months after bioprosthetic aortic valve replacement. We examined neurologic events within 90 days of bioprosthetic aortic valve replacement at our institution. METHODS: Between 1993 and 2000, 1151 patients underwent bioprosthetic aortic valve replacement with (641) or without (510) associated coronary artery bypass. By surgeon preference, 624 had early postoperative anticoagulation (AC+) and 527 did not (AC-). In the AC- group, 410 patients (78%) received antiplatelet therapy. Groups were similar with respect to gender (female, 36% AC+ vs 40% AC-, P = .21), hypertension (64% AC+ vs 61%, P = .27), and prior stroke (7.6% AC+ vs 8.5% AC-, P = .54). The AC+ group was slightly younger than the AC- group (median, 76 years vs 78 years, P = .006). RESULTS: Operative mortality was 4.1% with 43 (3.7%) cerebrovascular events within 90 days. Excluding 18 deficits apparent upon emergence from anesthesia, we found that postoperative cerebrovascular accident occurred in 2.4% of AC+ and 1.9% AC- patients. By multivariable analysis, the only predictor of operative mortality was hypertension ( P < .0001). Postoperative cerebrovascular accident was unrelated to warfarin use ( P = .32). The incidence of mediastinal bleeding requiring reexploration was similar (5.0% vs 7.4%), as were other bleeding complications in the first 90 days (1.1% vs 0.8%). No variables were predictive of bleeding by multivariate analysis. CONCLUSIONS: Although these data do not address the role of antiplatelet agents, early anticoagulation with warfarin after bioprosthetic aortic valve replacement did not appear to protect against neurologic events.