Pulmonary vascular mechanical consequences of ischemic heart failure and implications for right ventricular function.

Left heart failure (LHF) is the most common cause of pulmonary hypertension, which confers an increase in morbidity and mortality in this context. Pulmonary vascular resistance has prognostic value in LHF, but otherwise the mechanical consequences of LHF for the pulmonary vasculature and right ventricle (RV) remain unknown. We sought to investigate mechanical mechanisms of pulmonary vascular and RV dysfunction in a rodent model of LHF to address the knowledge gaps in understanding disease pathophysiology. LHF was created using a left anterior descending artery ligation to cause myocardial infarction (MI) in mice. Sham animals underwent thoracotomy alone. Echocardiography demonstrated increased left ventricle (LV) volumes and decreased ejection fraction at 4 wk post-MI that did not normalize by 12 wk post-MI. Elevation of LV diastolic pressure and RV systolic pressure at 12 wk post-MI demonstrated pulmonary hypertension (PH) due to LHF. There was increased pulmonary arterial elastance and pulmonary vascular resistance associated with perivascular fibrosis without other remodeling. There was also RV contractile dysfunction with a 35% decrease in RV end-systolic elastance and 66% decrease in ventricular-vascular coupling. In this model of PH due to LHF with reduced ejection fraction, pulmonary fibrosis contributes to increased RV afterload, and loss of RV contractility contributes to RV dysfunction. These are key pathologic features of human PH secondary to LHF. In the future, novel therapeutic strategies aimed at preventing pulmonary vascular mechanical changes and RV dysfunction in the context of LHF can be tested using this model. NEW & NOTEWORTHY In this study, we investigate the mechanical consequences of left heart failure with reduced ejection fraction for the pulmonary vasculature and right ventricle. Using comprehensive functional analyses of the cardiopulmonary system in vivo and ex vivo, we demonstrate that pulmonary fibrosis contributes to increased RV afterload and loss of RV contractility contributes to RV dysfunction. Thus this model recapitulates key pathologic features of human pulmonary hypertension-left heart failure and offers a robust platform for future investigations.

Superior survival in treatment of primary nonmetastatic pediatric osteosarcoma of the extremity.

BACKGROUND: A protocol to treat osteosarcoma of the extremity was developed at two local institutions. METHODS: The study involved a dose-intensified neoadjuvant protocol of intravenous doxorubicin and intra-arterial cisplatin administered repetitively until maximum angiographic response was noted. Definitive surgery was delayed until > or =90% reduction in tumor neovascularity was documented. Prospective assessment of serial arteriograms was highly accurate (94%) in predicting histological response and assisted in surgical planning. After resection, if patients were determined to be good responders (> or =90% tumor necrosis), they underwent a 4-month postoperative course with the same agents. Poor responders (<90% necrosis) were treated with alternative agents for 12 months from diagnosis. Forty-seven assessable patients with primary, high-grade, nonmetastatic osteosarcoma of the extremity were included in this analysis. The median age was 15 years (range, 7-21 years). RESULTS: Patients underwent an average of four preoperative intra-arterial courses. Forty-three patients underwent limb-preservation procedures, and 41 had >90% tumor necrosis. With an average follow-up of 92 months (range, 20-178 months), 39 patients were continuously disease free, 3 died of disease, 1 died of other causes, and 4 have no evidence of disease 11 to 51 months after relapse (all pulmonary metastases). There were no local recurrences. Kaplan-Meier analysis demonstrated a 10-year overall survival of 92% and an event-free survival of 84%. CONCLUSIONS: This study demonstrates excellent survival with a dose-intensified neoadjuvant protocol. Future endeavors should involve a multi-institutional randomized study comparing this approach with another multiagent intravenous neoadjuvant protocol.